SiC Liner Selective Removal via Plasma Treatment and Wet Etch
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Solution Overview
Problem
In the fabrication of memory devices, dry etch processes struggle to form small features with desired dimensions and profiles, often causing surface damage and undesirable profiles in underlying materials, leading to reduced electrical performance and potential shorting between adjacent features.
Innovation Solution
A silicon carbide material is used as a liner, conformally formed in small openings, and subjected to a plasma treatment to change its chemical composition, allowing selective removal of exposed portions by a wet etch process while unexposed portions remain, resulting in smaller feature sizes with improved profiles and reduced surface damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etch processes are used to remove portions of the liner, then portions of the liner can be removed, but surface damage is caused to underlying materials and undesirable profiles are produced
Solution Approach 1:
The patent changes the etching parameter by switching from dry etch to wet etch process. The wet etch process uses chemical solutions to remove the liner material selectively, avoiding the physical bombardment and ion damage caused by dry etch plasma, thereby preventing surface damage to underlying materials while achieving precise liner removal
Solution Approach 2:
The patent replaces the mechanical/physical dry etch process with a chemical wet etch process. Instead of using plasma and ion bombardment to remove the liner, chemical solutions are used to dissolve and remove the liner material selectively, eliminating the harmful mechanical effects on underlying materials
2Manufacturing precision
If dry etch processes are used to remove portions of the liner, then portions of the liner can be removed, but shoulders are produced in the underlying material leading to shorting
Solution Approach 1:
The patent changes the etching process parameter from dry to wet etch, which provides more uniform and controlled removal of the liner material. The wet etch process creates smoother sidewalls and prevents the formation of shoulders that could lead to shorting, while maintaining precise control over the final opening dimensions
Solution Approach 2:
The patent substitutes the dry etch mechanical removal process with a wet etch chemical dissolution process. This replacement eliminates the ion bombardment effects that cause shoulder formation and subsequent shorting between adjacent features, while maintaining the ability to achieve desired opening sizes
3Productivity
If feature sizes are reduced to increase integration density, then more features can be packed, but the ability to form openings at desired dimensions and selectively remove liner portions becomes harder
Solution Approach 1:
The patent changes the etching process parameter to wet etch, which provides better control and precision at smaller feature dimensions. The chemical etching mechanism maintains uniform removal rates and selective action even as feature sizes decrease, enabling continued scaling while preserving manufacturing capability
Solution Approach 2:
The patent replaces the dry etch process with wet etch to maintain manufacturing precision at reduced feature sizes. The chemical-based wet etch process provides more predictable and controllable liner removal at small dimensions, avoiding the difficulties associated with plasma-based dry etching at scaled dimensions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the formation of smaller features with improved electrical performance and reduced shorting by maintaining the integrity of underlying materials, achieving smaller dimensions and more precise profiles compared to conventional dry etch processes.
Implementation Method 1
The silicon carbide material of the liner is conformally formed in the openings. After formation, portions of the silicon carbide material are exposed to a plasma treatment act, which changes a chemical composition of the exposed portions of the liner.
Data Source
AI summary
An apparatus comprising active areas and shallow trench isolation structures on a base material. A first conductive material is vertically adjacent to an active area of the active areas and between laterally adjacent shallow trench isolation structures. A second conductive material is vertically adjacent to the first conductive material and between the laterally adjacent shallow trench isolation structures. A silicon carbide material is on sidewalls of the shallow trench isolation structures and exhibits substantially vertical sidewalls. An oxide material is adjacent to the active areas and shallow trench isolation structures, a nitride material is adjacent to the oxide material, and a digit line is adjacent to the second conductive material. An electronic system and methods of forming an apparatus are also disclosed.